feat: issue optional warning using '==' for wrapper types

org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/AbstractBatchCompilerTest.java

@@ -665,7 +665,8 @@ protected void runTest(boolean shouldCompileOK, String[] testFiles, Object extra
 					"Unexpected error output for invocation with arguments ["
 						+ extraArguments + "]",
 					expectedErrOutputString,
-					errOutputString);
+					outputDirNormalizer
+					.normalized(errOutputString));
 		}
 	}